1. Field of the Invention
The present invention relates to an electronic musical instrument, and more particularly to an electronic musical instrument having a keyboard whose key area can be divided for accompaniment and melody.
2. Prior Art
Conventionally, the electronic musical instrument provides a key area dividing unit by which the key area of keyboard is divided into two areas which are respectively used for the accompaniment and melody. In the key area for accompaniment, chord designation of automatic accompaniment and bass performance are executed in general (see Japanese Patent Laid-Open Publication No. 54-158216).
However, the above-mentioned key area diving unit must require a switch operation for setting the predetermined mode when the key area is to be divided. In addition, tone color setting of each key area must be executed by another independent operation. For this reason, the conventional electronic musical instrument is disadvantageous in that the operations of diving the key area must be complicated.
Meanwhile, the conventional electronic musical instrument may provide a tone area changing unit capable of changing the tone area of each divided key area as disclosed in Japanese Patent Publication No. 62-35118. This unit changes the tone area of each key area such that certain tone pitches will be assigned to both key areas. For example, certain tone pitches of melody performance can be set identical to those of chord performance. Thus, the electronic musical instrument having a single-stage keyboard can obtain the same performance effect of the electronic musical instrument having a plural-stage keyboard.
However, since the tone area of each divided key area is fixed in advance, freedom degree of changing the tone area must be limited. For example, it is impossible to change the tone area to the desirable tone area which is suitable for the tune to be performed by each time. In addition, the conventional tone area changing unit changes the tone areas such that these tone areas will be partially coincided with each other. Therefore, it is impossible to play the performance based on melody tones in upper key area and bass tones in lower key area whose tone pitches are respectively separated from each other.